Copy & Paste values if cell value = "N/A" - excel

Question

I want to copy and paste values to a range of cells but only if their value = "N/A". I want to leave the formulas as they are in all the cells that do not = "N/A".
In context, I have hundreds of VLOOKUPs. Example:
=IFERROR(VLOOKUP("L0"&MID(G$4,1,1)&"A0"&MID(G$4,1,1)&MID(G$4,3,2)&"-0"&$B6,Sheet1!$C:$D,2,FALSE),"N/A")
Is this possible with VBA?

Answer 1

First of all, you should use real error values rather than string that only look like errors. Secondly, VLOOKUP returns the N/A error directly if the lookup value is not found, so the IFERROR wrapper can be dispenced with. So the formula
=VLOOKUP("L0"&MID(G$4,1,1)&"A0"&MID(G$4,1,1)&MID(G$4,3,2)&"-0"&$B6,Sheet1!$C:$D,2,FALSE)
is sufficient as is.
To replace N/A results with error values, you can use this
Sub Demo()
Dim ws As Worksheet
Dim rngSrc As Range
Dim datV As Variant, datF As Variant
Dim i As Long
' Get range to process by any means you choose
' For example
Set ws = ActiveSheet
With ws
Set rngSrc = .Range(.Cells(1, 1), .Cells(.Rows.Count, 1).End(xlUp))
End With
' Copy data to variant arrays for efficiency
datV = rngSrc.Value
datF = rngSrc.Formula
' replace erroring formulas
For i = 1 To UBound(datV, 1)
If IsError(datV(i, 1)) Then
If datV(i, 1) = CVErr(xlErrNA) Then
datF(i, 1) = CVErr(xlErrNA)
End If
End If
Next
' return data from variant arrays to sheet
rngSrc.Formula = datF
End Sub
If you really want to use strings rather than true error values, adapt the If lines to suit

Answer 2

Rather than loop through all cells in a range, you can use SpecialCells to shorten working with the =NA()cells
This also open up a non-VBA method (if the only error cells are NA, ie no Div#/0)
The first two methods below (manual and code) deal with the situation where you only gave NA cells
the third uses SpecialCells to focus on only the cells that need to be tested, before then running a check for NA before making updates
option1
Manual selection of formula cells that evaluate to errors
Select the range of interest
Press [F5].
Click Special
Select Formulas
check only Errors
option2
VBA updating formula cells that evaluate to errors
code
Sub Shorter()
Dim rng1 As Range
On Error Resume Next
' All error formulas in column A
Set rng1 = Columns("A").SpecialCells(xlCellTypeFormulas, 16)
On Error GoTo 0
If rng1 Is Nothing Then Exit Sub
'update with new value (could be value or formulae)
rng1.Value = "new value"
End Sub
option 3
Test for =NA()
Sub TestSpecificRegion()
Dim rng1 As Range
Dim rng2 As Range
Dim X
Dim lngRow As Long
On Error Resume Next
' All error formulas in column A
Set rng1 = Columns("A").SpecialCells(xlCellTypeFormulas, 16)
On Error GoTo 0
If rng1 Is Nothing Then Exit Sub
'update with new value (could be value or formulae)
For Each rng2 In rng1.Areas
If rng2.Cells.Count > 1 Then
X = rng2.Value2
For lngRow = 1 To UBound(X, 1)
If X(lngRow, 1) = CVErr(xlErrNA) Then X(lngRow, 1) = "new value"
Next
rng2.Value = X
Else
If rng2.Value2 = CVErr(xlErrNA) Then rng2.Value = "new value"
End If
Next
End Sub